/*
 * Copyright 2019 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "modules/skottie/src/effects/Effects.h"

#include "include/private/base/SkTPin.h"
#include "modules/skottie/src/SkottieValue.h"
#include "modules/sksg/include/SkSGRenderEffect.h"
#include "src/utils/SkJSON.h"

namespace skottie {
namespace internal {
namespace {
class DropShadowAdapter final : public AnimatablePropertyContainer {
public:
    static sk_sp<DropShadowAdapter> Make(const skjson::ArrayValue &jprops, sk_sp<sksg::RenderNode> layer,
        const AnimationBuilder &abuilder)
    {
        enum : size_t {
            kShadowColor_Index = 0,
            kOpacity_Index = 1,
            kDirection_Index = 2,
            kDistance_Index = 3,
            kSoftness_Index = 4,
            kShadowOnly_Index = 5,
        };

        sk_sp<DropShadowAdapter> adapter(new DropShadowAdapter(std::move(layer)));

        EffectBinder(jprops, abuilder, adapter.get())
            .bind(kShadowColor_Index, adapter->fColor)
            .bind(kOpacity_Index, adapter->fOpacity)
            .bind(kDirection_Index, adapter->fDirection)
            .bind(kDistance_Index, adapter->fDistance)
            .bind(kSoftness_Index, adapter->fSoftness)
            .bind(kShadowOnly_Index, adapter->fShdwOnly);

        return adapter;
    }

    const sk_sp<sksg::RenderNode> &node() const
    {
        return fImageFilterEffect;
    }

private:
    explicit DropShadowAdapter(sk_sp<sksg::RenderNode> layer)
        : fDropShadow(sksg::DropShadowImageFilter::Make()),
          fImageFilterEffect(sksg::ImageFilterEffect::Make(std::move(layer), fDropShadow))
    {}

    void onSync() override
    {
        // fColor -> RGB, fOpacity -> A
        const SkColor color = fColor;
        fDropShadow->setColor(SkColorSetA(color, SkTPin(SkScalarRoundToInt(fOpacity), 0, 255)));

        // The offset is specified in terms of a bearing + distance.
        const auto rad = SkDegreesToRadians(90 - fDirection);
        fDropShadow->setOffset(SkVector::Make(fDistance * SkScalarCos(rad), -fDistance * SkScalarSin(rad)));

        const auto sigma = fSoftness * kBlurSizeToSigma;
        fDropShadow->setSigma(SkVector::Make(sigma, sigma));

        fDropShadow->setMode(SkToBool(fShdwOnly) ? sksg::DropShadowImageFilter::Mode::kShadowOnly :
                                                   sksg::DropShadowImageFilter::Mode::kShadowAndForeground);
    }

    const sk_sp<sksg::DropShadowImageFilter> fDropShadow;
    const sk_sp<sksg::RenderNode> fImageFilterEffect;

    ColorValue fColor = { 0, 0, 0, 1 };
    ScalarValue fOpacity = 255, fDirection = 0, fDistance = 0, fSoftness = 0, fShdwOnly = 0;
};
} // namespace

sk_sp<sksg::RenderNode> EffectBuilder::attachDropShadowEffect(const skjson::ArrayValue &jprops,
    sk_sp<sksg::RenderNode> layer) const
{
    return fBuilder->attachDiscardableAdapter<DropShadowAdapter>(jprops, std::move(layer), *fBuilder);
}
} // namespace internal
} // namespace skottie
